GB309162A - Improvements in or relating to sound radiating devices - Google Patents

Abstract

309,162. Victor Talking Machine Co., (Assignees of Williams, S. T.). April 6, 1928, [Convention date]. Loud-speakers; magnetic instruments. - A loud-speaker or other sound radiating device comprises a diaphragm having a horn loading each side thereof, the diaphragm being mounted within the space occupied by the horn structure and at least one of the horns comprising an amplifying passage formed between two surfaces of revolution, one of which surfaces is continuous from the edge of the diaphragm to the outlet end of the horn. According to a modified construction, a group of diaphragms arranged side by side is employed, in which case one of the surfaces of revolution forming the amplifying passage of a horn loading one side of the group of diaphragms is continuous from the edge of this group to the outlet of the horn. The mouths of the horns are preferably arranged to emit contiguous portions of a composite wave front and an external equalizing chamber is preferably provided between the outlets of the herns. One horn may extend transversely to the axis of the diaphragm, and one or both horns may comprise an amplifying passage formed between relatively flared similarly curved surfaces of revolution. In the loud-speaker shown in Fig. 2, the diaphragm 22 of a coil-driven unit 19 is loaded on one side by a horn 16 and on the other by a horn formed between a conical base member 1 and a shallow annular member 10 supported on sp@ers 13, the directions of wave emission being at a large angle. The base 1 may have supporting rings 3, 4. The relative dimensions of the two horns may be varied so as to obtain different operating characteristics. The horns may have cu@ed or reversely curved passages as shown in Fig. 8 in which the upper side of the diaphragm is loaded by the horn formed between conical members 27, 29, and the tubular wall 32 extending from the lower side of the diaphragm is flared radially and reversely curved at 33 and at 35, thereby forming with a correspondingly slipped member 37 annular portions 34<1> 36<1> surrounding the tubular part 32. To obtain directional characteristics, the horn at the back of the diaphragm may be extended and reversely curved so as to form an annular sound passage 42, Fig. 11, surrounding the horn 16. Two or more independent diaphragms may replace the single diaphragm, shown in Figs. 2, 8. 11. The loud speaker may be supported on a wall or ceiling or two loud-speakers may be supported back to Lack or on opposite walls of a room. Specification 5039/14, [Class 40 (ii), Phonographs &c. is referred to.